Semi-Precious Stones 189
when polished, its streak, when scratched, is red; hence the name hematite, meaning " bloodstone."
IOLITE,
also called dichroite and water sapphire, is a pleochroic mineral
occasionally Cut for gem purposes. It is somewhat harder than quartz.
JET
is a soft compact light coal of a lustrous velvet black colour, and can
be highly polished. It is used not polished for mourning goods. Jet was
the agates of the ancients, their source of supply being near the river
Gagas in Syria, from which the name of the mineral wTas derived.
LABEADOEITE,
sometimes, in the trade, called labrador, is a feldspar. Because of its
structure some of the varieties of labradorite reveal a wonderful
variety of colours. Labradorite can be highly polished and exhibits
beautiful chatoyant reflections.
LAPIS-LAZULI
was long regarded as a separate specific mineral; it was the sapphire
of the Greeks, Romans, and the Hebrew Scriptures. Instead of being a
simple mineral, lapis-lazuli consists of a bluish substance (lazurite)
with granular calcite, scapolite, diopside, amphibole mica, pyrite,
etc. The hardness of lapis-lazuli
